I have a centos server and I want to run a job on it at 11PM every 2 days, how do I do that?
In general, you need to use crontab to define the task and the run schedule.
crontab -e -u root
This will put you in VI editing root's crontab entry. Then as ewwhite says, enter:
0 23 */2 * * insert_your_script_here.sh
and then [^ESC] ZZ to save the changes.
This is a good first attempt, but this is not quite every alternate day, as it will run on the 30th of the month and then next run on the 2nd of the month. If you really do need it to be every 2nd day, then run the script EVERY night.
0 23 * * * insert_your_script_here.sh
and in the start of the script use
#/bin/sh if -f /tmp/altday.txt rm /tmp/altday.txt exit fi touch /tmp/altday.txt
This uses a text file to force the script to exit every alternate invocation.